There are no valid studies showing the vaccine for the human papillomavirus, or HPV, prevents cervical cancer. However, there are studies suggesting the vaccine could increase the risk of cancer.
By Dr. Yuhong Dong
Editor’s Note: This second installment in a multi-part series about the human papillomavirus, or HPV, vaccine examines studies that link the vaccines to increased risk of serious neurological and autoimmune disorders. Read Part 1 here and Part 2 here.
In part 3, we turn to questions regarding the effectiveness of the vaccine to prevent cervical cancer, and the limitations of relevant clinical trials to detect such a type of effect.
Summary of key facts
- There are multiple obstacles in designing a valid clinical trial to prove the HPV vaccine could prevent cervical cancer, e.g. long lead time, lack of adequate informed consent, complexity between HPV infection and cervical cancer and the negative impact of girls’ sexual behavior, which may worsen the risks of cervical cancer.
- Most of the HPV’s interventional clinical trials have too short a follow-up time to draw a concrete conclusion.
- In a large Swedish observational trial, which is treated as the most convincing study to prove the HPV vaccine’s effects on cervical cancer, a few confounding factors were not adequately balanced between the HPV vaccination group versus the unvaccinated group.
- The National Cancer Institute’s Surveillance, Epidemiology, and End Results Program (SEER) data and another U.S. study found the HPV vaccine has no effects in reducing cancer rates.
- Two other registry-based studies in Australia and the U.K. suggest that HPV vaccination is associated with increased cervical cancer rates in certain age groups.
Long lead time from HPV infection to cervical cancer
Typically, there is a long period from HPV infection to cervical epithelium abnormalities, then cervical cancer.
HPV infections usually last 12–18 months and are eventually cleared by the immune system.
Fewer than 10% of HPV infections are persistent….